CCNA Security Chapter 7 Exam Answer v2
What is the focus of cryptanalysis?
- hiding secret codes
- developing secret codes
- breaking encrypted codes
- implementing encrypted codes
How many bits does the Data Encryption Standard (DES) use for data encryption?
- 40 bits
- 56 bits
- 64 bits
- 72 bits
Which statement describes the Software-Optimized Encryption Algorithm (SEAL)?
- SEAL is a stream cipher.
- It uses a 112-bit encryption key.
- It is an example of an asymmetric algorithm.
- It requires more CPU resources than software-based AES does.
Which encryption algorithm is an asymmetric algorithm?
An online retailer needs a service to support the nonrepudiation of the transaction. Which component is used for this service?
- the private key of the retailer
- the unique shared secret known only by the retailer and the customer
- the public key of the retailer
- the digital signatures
In which situation is an asymmetric key algorithm used?
- Two Cisco routers authenticate each other with CHAP.
- User data is transmitted across the network after a VPN is established.
- An office manager encrypts confidential files before saving them to a removable device.
- A network administrator connects to a Cisco router with SSH.
What is the purpose of a nonrepudiation service in secure communications?
- to ensure that encrypted secure communications cannot be decoded
- to confirm the identity of the recipient of the communications
- to provide the highest encryption level possible
- to ensure that the source of the communications is confirmed
Which objective of secure communications is achieved by encrypting data?
Why is the 3DES algorithm often preferred over the AES algorithm?
- 3DES is more trusted because it has been proven secure for a longer period than AES.
- AES is more expensive to implement than 3DES.
- 3DES performs better in high-throughput, low-latency environments than AES.
- Major networking equipment vendors such as Cisco have not yet adopted AES.
What is the most common use of the Diffie-Helman algorithm in communications security?
- to create password hashes for secure authentication
- to provide routing protocol authentication between routers
- to encrypt data for secure e-commerce communications
- to secure the exchange of keys used to encrypt data
Which type of encryption algorithm uses public and private keys to provide authentication, integrity, and confidentiality?
- shared secret
How do modern cryptographers defend against brute-force attacks?
- Use statistical analysis to eliminate the most common encryption keys.
- Use a keyspace large enough that it takes too much money and too much time to conduct a successful attack.
- Use an algorithm that requires the attacker to have both ciphertext and plaintext to conduct a successful attack.
- Use frequency analysis to ensure that the most popular letters used in the language are not used in the cipher message.
Which encryption protocol provides network layer confidentiality?
- IPsec protocol suite
- Transport Layer Security
- Secure Hash Algorithm 1
- Secure Sockets Layer
- Keyed MD5
- Message Digest 5
Refer to the exhibit. Which encryption algorithm is described in the exhibit?
Which statement describes asymmetric encryption algorithms?
- They have key lengths ranging from 80 to 256 bits.
- They include DES, 3DES, and AES.
- They are also called shared-secret key algorithms.
- They are relatively slow because they are based on difficult computational algorithms.
Which two non-secret numbers are initially agreed upon when the Diffie-Hellman algorithm is used? (Choose two.)
- binomial coefficient
- elliptic curve invariant
- prime modulus
- topological index
- pseudorandom nome
In what situation would an asymmetric algorithm most likely be used?
- logging onto a computer
- making an online purchase
- uploading a networking book chapter using FTP
- transferring a large stream of data between two corporate locations
Why is asymmetric algorithm key management simpler than symmetric algorithm key management?
- It uses fewer bits.
- Only one key is used.
- Two public keys are used for the key exchange.
- One of the keys can be made public.
What is the purpose of code signing?
- source identity secrecy
- integrity of source .EXE files
- reliable transfer of data
- data encryption
Which algorithm can ensure data confidentiality?
What is the purpose of a digital certificate?
- It guarantees that a website has not been hacked.
- It authenticates a website and establishes a secure connection to exchange confidential data.
- It provides proof that data has a traditional signature attached.
- It ensures that the person who is gaining access to a network device is authorized.
Fill in the blank.
A shared secret is a key used in a symmetric encryption algorithm.